Nabi (sallallahu alaihi wasallam) said: “The expenses incurred during haj is like that incurred in jihad, rewarded seven hundred times.” (Musnad Ahmad #23000)
It is not possible for the material world to offer us an opportunity where we can invest our money and secure for ourselves a return which is seven hundred times over. Here on the occasion of haj we are rewarded seven hundred times for the money we spend during haj with rewards that are stored for us in the eternal vaults of the hereafter, where there is no fear of any deficiency, loss, or theft.